Optics

The microscope is undoubtedly the most important of all instruments. Although not as versatile as a pocket magnifying glass, it provides much greater magnification. In everyday practice, an expert is much more likely to have to distinguish natural stones from their synthetic counterparts and to identify imitations than to identify natural stones.

A microscope is absolutely necessary for detecting fakes. But its importance does not end there; the microscope is of great help when it is necessary to distinguish one stone from another, as it is possible to determine the nature of a specimen and even its mining location by examining inclusions in a stone under a microscope. It is also possible to determine the nature and depth of cracks, to detect the presence of birefringence and to estimate approximately its magnitude; with the help of immersion liquids or by "direct measurement", the refractive index can be determined.